Okokuqala, mayelana nokunikezwa kwamandla, amasignali avela emshinini wokubumba umjovo kanye nerobhothi adluliselwa ngokudluliselwa okuphakathi. Izimpahla zabo zamandla zizimele, okusiza ukuthuthukisa ukuzinza kwazo. Ukuthi isiginali iyasebenza phezulu noma phansi akucaciswanga kuzinga laseYurophu; kuchazwa umshini wokubumba umjovo kanye nabakhiqizi bamarobhothi ngokwabo. Izinga laseYurophu lichaza kuphela isimo sokuvula/ukuvala samaredi amaphakathi.
Isibonelo, uma umkhiqizi womshini wokubumba umjovo edinga ukuchaza "ukuvalwa kwesikhunta okuvunyelwe" njengokusebenzayo kuphansi, khona-ke ugesi ongu-0V unikezwa iphinikhodi engu-32-yephinikhodi "yomshini wokubumba umjovo". Lapho irobhothi livumela ukuvala isikhunta, i-relay emaphakathi ehambisanayo iyavala, idonse isignali ku-pin 17 low. Ngokufanayo, uma isignali esebenzayo yezinga eliphezulu idingeka, i-24VDC evela emshinini wokubumba umjovo ixhunywe kuphini elingu-32.
Mayelana nezimpawu zokumisa izimo eziphuthumayo namasignali edivayisi yokuphepha, i-European Standard 67 inesiginali eyodwa ngaphezu kwe-European Standard 12. Ngokwezinga lase-Europe, indawo yokusebenza yerobhothi idinga ukubiywa ukuze ivikeleke, ngakho isitobhi esiphuthumayo nesisheke sedivayisi yokuphepha sidinga ukufakwa ocingweni.
Isiginali ye-"Mold Area" ilawulwa amaswishi amabili kagesi engalweni yerobhothi. Lezi zinguquko ziqapha ukuthi ingalo yerobhothi ingaphakathi kwendawo yokukhunta. Uma kunjalo, umshini wokubumba umjovo kufanele uvinjelwe ukuvala isikhunta. Lesi siginali sihluka kancane kwezinye. Uma ingalo yerobhothi ingekho ngaphakathi kwendawo yokubumba, i-intermediate relay iyavala. Uma umshini wokubumba umjovo uchaza-isignali esebenzayo yezinga eliphezulu, ulayini wesignali ohambisanayo uzoba phezulu. Lapho ingalo yerobhothi ingena endaweni yesikhunta, i-relay ephakathi iyavuleka, futhi umugqa wesignali uya phansi.
Isignali ethi "Xhuma Umshini Wokubumba Umjovo" isetshenziswa uma ingalo yerobhothi idinga ukusetshenziswa. Ukunika amandla lesi siginali kuhlanganisa umshini wokubumba umjovo ngengalo yerobhothi. Ukuvula nokuvala komshini wokubumba umjovo, izikhonkwane ze-ejector, nezenzo zokudonsa eziyinhloko kulawulwa ingalo yerobhothi. Uma lesi siginali sikhutshaziwe, ingalo yerobhothi nomjovo wokubumba umshini usebenza ngokuzimela.
